U.S. patent number 10,549,643 [Application Number 15/232,554] was granted by the patent office on 2020-02-04 for controlled pre-charge circuit arrangement.
This patent grant is currently assigned to Ford Global Technologies, LLC. The grantee listed for this patent is FORD GLOBAL TECHNOLOGIES, LLC. Invention is credited to Robert Bolduc, Wesley Edward Burkman, Arnold Kweku Mensah-Brown, Benjamin A. Tabatowski-Bush.
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United States Patent |
10,549,643 |
Tabatowski-Bush , et
al. |
February 4, 2020 |
Controlled pre-charge circuit arrangement
Abstract
A vehicle system includes a relay and coil of a contactor. The
relay is configured to transfer current between a traction battery
and an electrical load when closed. The system also includes a
controller configured to operate a switch such that current flow
from the traction battery through the coil and switch, and
bypassing the relay, causes the relay to close to permit
pre-charging of the load.
Inventors: |
Tabatowski-Bush; Benjamin A.
(South Lyon, MI), Mensah-Brown; Arnold Kweku (Canton,
MI), Burkman; Wesley Edward (Dearborn, MI), Bolduc;
Robert (Northville, MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
FORD GLOBAL TECHNOLOGIES, LLC |
Dearborn |
MI |
US |
|
|
Assignee: |
Ford Global Technologies, LLC
(Dearborn, MI)
|
Family
ID: |
61018771 |
Appl.
No.: |
15/232,554 |
Filed: |
August 9, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180043783 A1 |
Feb 15, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
15/2072 (20130101); B60L 1/00 (20130101); B60L
11/1803 (20130101); B60L 50/51 (20190201); Y02T
10/70 (20130101); Y02T 10/64 (20130101); Y02T
10/72 (20130101); B60L 2270/20 (20130101); Y02T
10/7005 (20130101); Y02T 10/645 (20130101); Y02T
10/7275 (20130101) |
Current International
Class: |
B60L
50/51 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Fureman; Jared
Assistant Examiner: Bukhari; Aqeel H
Attorney, Agent or Firm: Kelley; David B. Brooks Kushman
P.C.
Claims
What is claimed is:
1. A vehicle system comprising: a contactor including a relay and
coil, the relay configured to transfer current between a traction
battery and an electrical load when closed; and a controller
configured to operate a switch such that current flow from the
traction battery through the coil and switch, and bypassing the
relay, causes the relay to close to permit pre-charging of the
load.
2. The system of claim 1, wherein the relay and coil are connected
in series and define a pre-charge contactor configured to open
responsive to pre-charge completion.
3. The system of claim 1, wherein the relay and coil define a main
contactor configured to remain closed responsive to pre-charge
completion.
4. The system of claim 1, wherein the controller is further
configured to operate the switch such that the causing of the relay
to close permits pre-charging of the load to a first threshold, and
to subsequently operate the switch to permit pre-charging of the
load to a second threshold.
5. The system of claim 4, wherein the second threshold is greater
than the first threshold.
6. The system of claim 4, wherein the first threshold corresponds
to a voltage measured across a relay bypass path and wherein the
second threshold corresponds to a voltage measured across the
battery.
7. The system of claim 6, wherein pre-charging the load to a
voltage measured across the battery is indicative of pre-charge
completion.
8. The system of claim 1 further comprising a resistor connected
with the relay and coil such that amount of current bypassing the
relay is greater than a pull-in current that causes the relay to
close and less than an upper-bound current that causes a
temperature of the coil to exceed a predefined value.
9. A system for a traction battery comprising: a contactor
including a coil and relay connected in series, the relay
configured to close in response to a magnitude of current through
the coil being greater than a first threshold; and a controller
configured to, responsive to a pre-charge request, enable current
from the battery to flow through the coil and bypass the relay such
that a magnitude of the current from the battery is less than a
second threshold greater than the first prior to the relay closing
to pre-charge an electrical load.
10. The system of claim 9, wherein pre-charging the load includes
causing a voltage of the load to correspond to a voltage across a
relay bypass path.
11. The system of claim 9, wherein the controller is further
configured to disable current flow through the coil and relay in
response to a voltage of the load corresponding to a voltage of the
battery.
12. A method for a traction battery comprising: in response to
receiving a pre-charge request, by a controller, selectively
enabling current from the battery to flow through a coil of a
contactor and to bypass a relay of the contactor prior to closing
of the relay to permit pre-charging of a load to a first threshold
voltage.
13. The method of claim 12 further comprising, responsive to the
pre-charging of the load to the first threshold voltage,
selectively enabling current from the battery to flow through the
coil and relay to permit pre-charging of the load to a second
threshold voltage greater than the first.
14. The method of claim 13, wherein the first threshold voltage
corresponds to a voltage across a relay bypass path and the second
threshold voltage corresponds to a voltage across the battery.
15. The method of claim 14, wherein the pre-charging the load to a
voltage across the battery is indicative of pre-charge
completion.
16. The method of claim 12, wherein the contactor is a pre-charge
contactor configured to open in response to pre-charge
completion.
17. The method of claim 12, wherein the contactor is a main
contactor configured to remain closed following pre-charge
completion to permit transfer of charge between the battery and the
load.
Description
TECHNICAL FIELD
The present disclosure relates to systems and methods for arranging
one or more components in a circuit for controlling pre-charge of
an electrical load.
BACKGROUND
A hybrid or an electric vehicle may be equipped with at least one
traction battery configured to provide energy for propulsion. The
traction battery may also provide energy for other vehicle
electrical systems. For example, the traction battery may transfer
energy to high voltage loads, such as compressors and electric
heaters. In another example, the traction battery may provide
energy to low voltage loads, such as an auxiliary 12V battery.
SUMMARY
A vehicle system includes a relay and coil of a contactor, the
relay configured to transfer current between a traction battery and
an electrical load when closed, and a controller configured to
operate a switch such that current flow from the traction battery
through the coil and switch, and bypassing the relay, causes the
relay to close to permit pre-charging of the load.
A system for a traction battery includes a contactor including a
coil and relay connected in series, the relay configured to close
in response to a magnitude of current through the coil being
greater than a first threshold, and a controller configured to,
responsive to a pre-charge request, enable current from the battery
to flow through the coil and bypass the relay such that a magnitude
of the current from the battery is less than a second threshold
greater than the first prior to the relay closing to pre-charge an
electrical load.
A method for a traction battery includes, in response to receiving
a pre-charge request, by a controller, selectively enabling current
from the battery to flow through a coil of a contactor and to
bypass a relay of the contactor prior to closing of the relay to
permit pre-charging of a load to a first threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of hybrid electric vehicle (HEV)
illustrating a typical drivetrain and energy storage
components;
FIG. 2A is a schematic diagram illustrating an arrangement for
pre-charging an electrical load;
FIG. 2B is a schematic diagram illustrating a contactor;
FIG. 3 is a schematic diagram illustrating a controlled pre-charge
circuit arrangement using a pre-charge contactor coil as a
pre-charge resistor;
FIG. 4 is a schematic diagram illustrating a controlled pre-charge
circuit arrangement using a main contactor coil to pre-charge a
load;
FIG. 5 is a flowchart illustrating an algorithm for controlling
pre-charge of the load using a pre-charge contactor coil as a
pre-charge resistor; and
FIG. 6 is a flowchart illustrating an algorithm for controlling
pre-charge of the load using a main contactor coil.
DETAILED DESCRIPTION
Embodiments of the present disclosure are described herein. It is
to be understood, however, that the disclosed embodiments are
merely examples and other embodiments may take various and
alternative forms. The figures are not necessarily to scale; some
features could be exaggerated or minimized to show details of
particular components. Therefore, specific structural and
functional details disclosed herein are not to be interpreted as
limiting, but merely as a representative basis for teaching one
skilled in the art to variously employ the present invention. As
those of ordinary skill in the art will understand, various
features illustrated and described with reference to any one of the
figures may be combined with features illustrated in one or more
other figures to produce embodiments that are not explicitly
illustrated or described. The combinations of features illustrated
provide representative embodiments for typical applications.
Various combinations and modifications of the features consistent
with the teachings of this disclosure, however, could be desired
for particular applications or implementations.
FIG. 1 depicts an example hybrid-electric vehicle (HEV) system 10.
A hybrid-electric vehicle 12, hereinafter vehicle 12, may comprise
at least one traction battery 14. The traction battery 14 may
include a battery controller 16 and may be configured to receive
electric charge via a charging session at a charging station
connected to a power source. In one example, the power source may
include a device that harnesses renewable energy, such as a
photovoltaic (PV) solar panel, or a wind turbine.
The traction battery 14 may comprise one or more battery cells (not
shown), e.g., electrochemical cells, capacitors, or other types of
energy storage device implementations. The battery cells may be
arranged in any suitable configuration, such as, but not limited
to, in series and in parallel, and configured to receive and store
electric energy for use in operation of the vehicle 12. Each cell
may provide a same or different nominal threshold of voltage. The
battery cells may be further arranged into one or more arrays,
sections, or modules further connected in series or in
parallel.
The traction battery 14 further comprises a bussed electrical
center (BEC) 18 electrically connected to the battery cells, e.g.,
such as via positive and negative battery terminals. The BEC 18 may
include a plurality of connectors and switches enabling the supply
and withdrawal of electric energy to and from the battery cells of
the traction battery 14. In one example, the BEC 18 may be
electrically connected with the battery controller 16 and may be
configured to receive one or more commands, signals, or other
notifications from the battery controller 16 indicative of a
request to operate the one or more of the plurality of connectors
and switches.
The battery controller 16 is electrically connected with the BEC 18
and controls the energy flow between the BEC 18 and the battery
cells. For example, the battery controller 16 may be configured to
monitor and manage temperature and state of charge of each of the
battery cells. The battery controller 16 may, in one instance,
command the BEC 18 to operate one or more of the plurality of
switches in response to temperature or state of charge in a given
battery cell reaching a predefined threshold. In another example,
the battery controller 16 may be in communication with one or more
vehicle controllers 38, such as, but not limited to, an engine
controller (ECM) and transmission controller (TCM), and may command
the BEC 18 to operate one or more of the plurality of switches in
response to a predetermined signal from the one or more vehicle
controllers 38.
The vehicle 12 may further comprise one or more electric machines
22 mechanically connected to a hybrid transmission 24. The electric
machines 22 may be capable of operating as a motor or a generator.
In addition, the hybrid transmission 24 may be mechanically
connected to an engine 26. The hybrid transmission 24 is also
mechanically connected to a drive shaft 28 that is mechanically
connected to wheels 30.
The electric machines 22 can provide propulsion and deceleration
capability when the engine 26 is turned on or off using energy
stored in the traction battery 14, such as via the BEC 18. The
electric machines 22 also act as generators and can provide fuel
economy benefits by recovering energy that would normally be lost
as heat in the friction braking system. The electric machines 22
may also provide reduced pollutant emissions since the vehicle 12
may be operated in electric mode under certain conditions.
The traction battery 14 typically provides a high voltage DC
output. The BEC 18 of the traction battery 14 may be electrically
connected to an inverter system controller (ISC) 32. The ISC 32 is
electrically connected to the electric machines 22 and provides the
ability to bi-directionally transfer energy, such as via the BEC
18, between the traction battery 14 and the electric machines 22.
In one example, the electric machines 22 and other components of
the vehicle 12 supplying and/or receiving energy to and from the
traction battery 14 may define a main load 34 of the traction
battery 14.
In a motor mode, the ISC 32 may convert the DC output provided by
the traction battery 14 to a three-phase alternating current (AC)
as may be required for proper functionality of the electric
machines 22. In a regenerative mode, the ISC 32 may convert the
three-phase AC output from the electric machines 22 acting as
generators to DC input required by the traction battery 14. While
FIG. 1 depicts a typical hybrid electric vehicle, the description
herein is equally applicable to a pure electric vehicle. For a pure
electric vehicle, e.g., battery electric vehicle (BEV), the hybrid
transmission 24 may be a gear box connected to the electric
machines 22 and the engine 26 may not be present. In one example, a
main load 34 of the traction battery 14 in the BEV may include the
electric machines 22 and the gear box.
In addition to providing energy for propulsion, the traction
battery 14 may provide energy for other vehicle electrical systems
(shown generally as auxiliary loads 36). For example, the traction
battery 14 may transfer energy to high voltage loads, such as
compressors and electric heaters. In another example, the traction
battery 14 may provide energy to low voltage loads, such as an
auxiliary 12V battery. In such an example, the vehicle 12 may
include a DC/DC converter module (not shown) that converts the high
voltage DC output of the traction battery 14 to a low voltage DC
supply that is compatible with the low voltage loads. The various
components discussed may have one or more associated controllers to
control and monitor the operation of the components. The
controllers may communicate via a serial bus (e.g., Controller Area
Network (CAN)) or via discrete conductors.
Referring now to FIG. 2A, an example arrangement 40 of the BEC 18
for energy transfer between the traction battery 14 and the main
load (indicated generally using a capacitor symbol) 34 is shown.
The arrangement 40 may include a pair of contactors 42a, 42b, such
as a positive main contactor and a negative main contactor,
electrically connected to corresponding terminals of the traction
battery 14. In one example, closing the contactors 42a, 42b
completes a circuit between the main load 34 and the traction
battery 14 allowing the flow of electric energy between the
traction battery 14 and the main load 34. In another example,
opening one or more of the contactors 42a, 42b opens the circuit
between the main load 34 and the traction battery 14 stopping the
flow of energy between them. In one instance, the battery
controller 16 may command the BEC 18 to open or close one or more
of the contactors 42a, 42b in response to receiving a signal from
the one or more vehicle controllers 38, e.g., ECM, TCM, and so on,
indicative of a request to initiate or terminate transfer of
electric energy between the main load 34 and the traction battery
14.
The arrangement 40 may further comprise a pre-charge circuit 44
configured to control an energizing process of the main load 34.
The pre-charge circuit 44 may include a pre-charge contactor 46
connected in series with a pre-charge resistor 48. The pre-charge
circuit 44 may be electrically connected in parallel with the
contactor 42a, such that when the contactor 42a is open, and the
pre-charge contactor 46 and the contactor 42b are closed, electric
current may flow through the pre-charge circuit 44 providing
controlled energizing of the terminal of the main load 34 that is
connected with the contactor 42a.
In one example, the battery controller 16 may be configured to
initiate a pre-charge procedure using the pre-charge circuit 44 in
response to receiving a signal indicative of a request to close the
contactors 42a, 42b. The battery controller 16 may, for example,
issue one or more commands to the BEC 18 to close the contactor 42b
and to close the pre-charge contactor 46 and control current flow
toward the terminal of the traction battery 14 in connection with
the contactor 42a.
The battery controller 16 may be also configured to terminate the
pre-charge procedure in response to voltage across the open
contactor, e.g., the contactor 42a, being greater than a predefined
threshold. The battery controller 16 may be further configured to
command the BEC 18 to close the contactor 42a in response to
voltage across the open contactor 42a being lower than a predefined
threshold.
As shown in FIG. 2B, each of the contactors 42a, 42b and the
pre-charge contactor 46 may define an electro-mechanical device 50
comprising an inductive coil 52 and a relay 54. In one example,
energizing the inductive coil 52 using a predefined amount of
current, e.g., pull-in current I.sub.pull_in, causes the relay 54
to close and de-energizing the inductive coil 52, e.g., providing
amount of current less than drop-out current I.sub.drop_out, causes
the relay 54 to open. In another example, following the closing of
the relay 54, the electro-mechanical device 50 may be configured to
conduct a predefined amount of current, e.g., hold current
I.sub.hold, through the inductive coil 52 to keep the relay 54 in a
closed position.
In one instance, pull-in current I.sub.pull_in may be larger than
hold current I.sub.hold and larger than drop-out current
I.sub.drop_out. In such an instance, hold current I.sub.hold may be
larger than drop-out current I.sub.drop_out. A value of pull-in
current I.sub.pull_in may, for example, be 1.7 amperes (A) with a
corresponding value of hold current I.sub.hold being 0.4 A and a
corresponding value of drop-out current I.sub.drop_out being 0.1 A.
Values of pull-in current I.sub.pull_in, hold current I.sub.hold,
and drop-out current I.sub.drop_out for a given contactor may be a
function of one or more device characteristics, such as, but not
limited to, design and manufacturer specifications, manufacturing
methods and materials, testing, contactor age and/or cycling count,
and so on.
In reference to FIG. 3, an exemplary arrangement 58 for controlling
a pre-charge of the main load 34 is shown. As described in
reference to FIG. 2A, the battery controller 16 may initiate a
procedure for pre-charging the main load 34 in response to
receiving a request to transfer energy between the traction battery
14 and the main load 34 or another signal indicative of a request
to close the contactors 42a, 42b. Responsive to the request, the
battery controller 16 may issue a command to close the contactor
42b. The battery controller 16 may be configured to pre-charge the
main load 34 using one or more active and/or passive circuit
components, such as, but not limited to, a pre-charge contactor
46a, a diode 64, a switch 66 and a resistor 68.
The pre-charge contactor 46a may include a pre-charge contactor
coil 60 and a pre-charge contactor relay 62 as was described, for
example, in reference to the electro-mechanical device 50
illustrated in FIG. 2B. In one example, the pre-charge contactor
coil 60 and the pre-charge contactor relay 62 may be connected in
series, such as via an external and/or an internal coupling of one
or more corresponding electrical leads. A series connection between
the pre-charge contactor coil 60 and the pre-charge contactor relay
62 may enable a controlled pre-charge of the main load 34.
Supplying power to the pre-charge contactor coil 60 may cause the
pre-charge contactor coil 60 to conduct current I.sub.coil in one
or more portions of the exemplary arrangement 58, e.g., due to an
intrinsic resistance of the pre-charge contactor coil 60. The
pre-charge contactor relay 62 may be configured to close, thus
beginning a pre-charge of the main load 34, in response to current
I.sub.coil through the pre-charge contactor coil 60 being greater
than a predefined threshold. In one example, the pre-charge
contactor relay 62 may be configured to close in response to
current I.sub.coil flowing through the pre-charge contactor coil 60
being greater than pull-in current I.sub.pull_in.
The switch 66, e.g., when in a closed state, may be electrically
connecting the pre-charge contactor 46a to the traction battery 14
enabling the pre-charge contactor 46a to be selectively powered
using high-voltage (HV) power using, for example, DC output of the
traction battery 14. In response to a predefined signal or request,
the battery controller 16 may be configured to selectively close
the switch 66 to complete the electrical circuit directing power to
the pre-charge contactor coil 60 of the pre-charge contactor 46a
and bypassing the pre-charge contactor relay 62 of the pre-charge
contactor 46a. In one example, the battery controller 16 may issue
a command to close the switch 66 in response to receiving a signal
indicative of a request to close the contactors 42a, 42b. The diode
64 may be configured to connect the main load 34 to the pre-charge
contactor 46a and may be configured to prevent a reverse current
flow into the traction battery 14.
In one instance, performance of the pre-charge contactor relay 62
may be affected in response to current flowing through one or more
portions of the exemplary arrangement 58, such as through the
pre-charge contactor coil 60, being greater than a predefined
threshold, e.g., greater than upper-bound current
I.sub.upper_bound, where upper-bound current I.sub.upper_bound is
greater than pull-in current I.sub.pull_in. The resistor 68 may be
arranged with the pre-charge contactor coil 60 and the pre-charge
contactor relay 62 of the pre-charge contactor 46a to reduce
current flow through one or more portions of the exemplary
arrangement 58 to be less than a predefined threshold, e.g.,
upper-bound current I.sub.upper_bound. The resistor 68 may be
arranged, for example, to reduce current through the pre-charge
contactor coil 60 to be less than upper-bound current
I.sub.upper_bound. In another example, the resistor 68 may be
arranged with the pre-charge contactor coil 60 and the pre-charge
contactor relay 62 of the pre-charge contactor 46a to maintain
current flow through one or more portions of the exemplary
arrangement 58 being greater than a predefined threshold, e.g.,
pull-in current I.sub.pull_in. The resistor 68 may be arranged, in
one instance, to maintain current flow through the pre-charge
contactor coil 60 being greater than pull-in current
I.sub.pull_in.
Following the closing of the pre-charge contactor relay 62 the
exemplary arrangement 58 may initiate a first stage of pre-charging
the main load 34, e.g., a first of a plurality of stages of a
pre-charging process. The first stage of pre-charging the main load
34 may include pre-charging the main load 34 to a predefined
threshold, such as to voltage greater than or equal to voltage drop
across the bypass path, e.g., the current path including the
pre-charge contactor coil 60 and the switch 66 and excluding the
pre-charge contactor relay 62. The battery controller 16 may be
configured to determine whether the first stage of pre-charging the
main load 34 has been completed. In one example, the battery
controller 16 may determine whether the first stage of pre-charging
the main load 34 has been completed based on voltage across the
open contactor 42a. The battery controller 16 may, in one instance,
determine that the first stage of pre-charging the main load 34 has
been completed in response to voltage across the open contactor 42a
being less than a predefined threshold, e.g., less than voltage
drop across the resistor 68.
The battery controller 16 may be further configured to, responsive
to determining that the first stage of pre-charging the main load
34 has been completed, issue one or more commands to open the
switch 66. Opening of the switch 66 may increase current flow
through the pre-charge contactor relay 62 and may thus initiate a
second stage of pre-charging the main load 34. The second stage of
pre-charging the main load 34 may include pre-charging the main
load to a predefined threshold, such as to voltage less than or
equal to voltage across the traction battery 14. As with the first
stage of pre-charging the main load 34, the battery controller 16
may determine whether the second stage of pre-charging the main
load 34 is completed based, for example, on voltage across the open
contactor 42a. The battery controller 16 may issue one or more
commands to close the contactor 42a in response to determining the
second stage of pre-charging the main load 34 is completed, e.g.,
in response to determining that voltage across the open contactor
42a is less than a predefined threshold. In one example, completion
of the second stage of pre-charging of the main load 34 may be
indicative of pre-charge completion.
In reference to FIG. 4, an exemplary arrangement 70 for controlling
a pre-charge of the main load 34 is shown. The contactors 42c, 42d,
when closed, may be configured to connect the traction battery 14
and the main load 34 thus enabling a transfer of electrical power,
e.g., via electrical current flow, between the two systems. The
battery controller 16 may initiate pre-charging of the main load 34
in response to receiving a request to transfer energy between the
traction battery 14 and the main load 34 or another signal
indicative of a request to close the contactors 42c, 42d. A diode
80 may be configured to connect the main load 34 to the contactor
42c and may be configured to prevent a reverse current flow into
the traction battery 14.
In initiating pre-charging of the main load 34 the battery
controller 16 may issue a command to close a switch 76 and initiate
current flow from the traction battery 14 to a contactor coil 74 of
the contactor 42c. A contactor relay 72 of the contactor 42c may be
configured to close, thus beginning a pre-charge of the main load
34, in response to current I.sub.coil through the contactor coil 74
being greater than a predefined threshold. In one example, the
contactor relay 72 may be configured to close in response to
current I.sub.coil flowing through the contactor coil 74 being
greater than pull-in current I.sub.pull_in.
In one instance, performance of the contactor relay 72 may be
affected in response to current flowing through one or more
portions of the exemplary arrangement 70, such as through the
contactor coil 74, being greater than a predefined threshold, e.g.,
greater than upper-bound current I.sub.upper_bound, where
upper-bound current I.sub.upper_bound is greater than pull-in
current I.sub.pull_in. The resistor 78 may be arranged with the
contactor coil 74 and the contactor relay 72 of the contactor 42c
to reduce current flow through one or more portions of the
exemplary arrangement 70 to be less than a predefined threshold,
e.g., upper-bound current I.sub.upper_bound. The resistor 78 may be
arranged, for example, to reduce current through the contactor coil
74 to be less than upper-bound current I.sub.upper_bound. In
another example, the resistor 78 may be arranged with the contactor
coil 74 and the contactor relay 72 of the contactor 42c to maintain
current flow through one or more portions of the exemplary
arrangement 70 being greater than a predefined threshold, e.g.,
pull-in current I.sub.pull_in. The resistor 78 may be arranged, in
one instance, to maintain current flow through the contactor coil
74 being greater than pull-in current I.sub.pull_in.
Following the closing of the contactor relay 72 the exemplary
arrangement 70 may initiate a first stage of pre-charging the main
load 34, e.g., a first of a plurality of stages of a pre-charging
process. The first stage of pre-charging the main load 34 may
include pre-charging the main load 34 to a predefined threshold,
such as to voltage greater than or equal to voltage drop across the
bypass path, e.g., the current path including the switch 76 and the
contactor coil 74 and excluding the contactor relay 72. The battery
controller 16 may be configured to determine whether the first
stage of pre-charging the main load 34 has been completed. In one
example, the battery controller 16 may determine whether the first
stage of pre-charging the main load 34 has been completed based on
voltage across one or more of the contactors 42c, 42d. The battery
controller 16 may, in one instance, determine that the first stage
of pre-charging the main load 34 has been completed in response to
voltage across one or more of the contactors 42c, 42d being less
than a predefined threshold, e.g., less than voltage drop across
the resistor 78.
The battery controller 16 may be further configured to, responsive
to determining that the first stage of pre-charging the main load
34 has been completed, issue one or more commands to open the
switch 76. Opening of the switch 76 may increase current flow
through the contactor relay 72 and may thus initiate a second stage
of pre-charging the main load 34. The second stage of pre-charging
the main load 34 may include pre-charging the main load to a
predefined threshold, such as to voltage less than or equal to
voltage across the traction battery 14. As with the first stage of
pre-charging the main load 34, the battery controller 16 may
determine whether the second stage of pre-charging the main load 34
is completed based, for example, on voltage across one or more of
the contactor 42c, 42d. In response to determining that the second
stage of pre-charging the main load 34 has been completed, the
battery controller 16 may issue one or more commands to operate the
switch 76 at a predefined duty cycle, e.g., such that current
flowing through the contactor coil 74 is greater than hold current
I.sub.hold. The battery controller 16 may further issue one or more
commands to close the contactor 42d in response to determining the
second stage of pre-charging the main load 34 is completed, e.g.,
in response to determining that voltage across the contactor 42d is
less than a predefined threshold. In one example, completion of the
second stage of pre-charging of the main load 34 may be indicative
of pre-charge completion.
In reference to FIG. 5, an example process 82 for controlling a
pre-charge of the main load 34 is shown. The process 82 may begin
at block 84 where the battery controller 16 receives a signal
indicative of a request to close the contactors 42a, 42b. In
response to the request, the battery controller 16 may begin a
process for pre-charging the main load 34. In one example, the
battery controller 16 may at block 86 issue a command to close the
contactor 42b.
At block 88 the battery controller 16 may issue a command to close
the switch 66 thus directing current to the pre-charge contactor
coil 60 of the pre-charge contactor 46a and the resistor 68.
Current I.sub.coil flowing through the pre-charge contactor coil 60
that is greater than pull-in current I.sub.pull_in may cause the
pre-charge contactor relay 62 to close, thus beginning a pre-charge
of the main load 34. The resistor 68 arranged with the pre-charge
contactor coil 60 and the pre-charge contactor relay 62 of the
pre-charge contactor 46a may reduce current through the pre-charge
contactor coil 60 to be less than upper-bound current
I.sub.upper_bound and may further maintain current I.sub.coil
flowing through the pre-charge contactor coil 60 being greater than
pull-in current I.sub.pull_in, where upper-bound current
I.sub.upper_bound is greater than pull-in current
I.sub.pull_in.
Following closing of the pre-charge contactor relay 62 that may
initiate a first stage of pre-charging the main load 34, the
battery controller 16 may be configured to at block 90 determine
whether the first stage of pre-charging the main load 34 has been
completed, such as based on voltage across the open contactor 42a.
In one example, the battery controller 16 may measure voltage
across the open contactor 42a for a predefined period of time
and/or a predefined number of times prior to determining whether a
pre-charge of the main load 34 has been completed. At block 92 the
battery controller 16 may issue a diagnostic message in response to
determining at block 90 that the first stage of pre-charging the
main load 34 has not been completed, e.g., voltage across the open
contactor 42a is greater than a voltage drop across the resistor 68
after a predefined period of time.
In response to determining at block 90 that the first stage of
pre-charging the main load 34 has been completed, the battery
controller 16 may at block 94 issue a command to open the switch 66
initiating a second stage of pre-charging the main load 34. At
block 96 the battery controller 16 may be configured to determine
whether the second stage of pre-charging the main load 34 has been
completed, such as based on voltage across the open contactor 42a
after a predefined period of time. At block 92 the battery
controller 16 may issue a diagnostic message in response to
determining at block 96 that the second stage of pre-charging the
main load 34 has not been completed, e.g., voltage across the open
contactor 42a is greater than a predefined threshold after a
predefined period of time.
In response to determining at block 96 that the second stage of
pre-charging the main load 34 has been completed, the battery
controller 16 may at block 98 issue one or more commands to close
the contactor 42a. The battery controller 16 may, in one instance,
determine that a pre-charge of the main load 34 has been completed
in response to voltage across the open contactor 42a being less
than a predefined threshold. The process 82 may then end. In some
instances, the process 82 may be repeated in response to receiving
a signal indicative of a request to close the contactors 42a, 42b
or in response to another signal or request.
In reference to FIG. 6, an example process 100 for controlling a
pre-charge of the main load 34 is shown. The process 100 may begin
at block 102 where the battery controller 16 receives a signal
indicative of a request to close the contactors 42c, 42d. In
response to the request, the battery controller 16 may begin a
process for pre-charging the main load 34. In one example, the
battery controller 16 may at block 104 issue a command to close the
switch 76 thus directing power to the contactor coil 74 of the
contactor 42c and the resistor 78. In one example, supplying power
to the contactor coil 74 and the resistor 78 may cause the
contactor coil 74 to conduct current I.sub.coil. Current I.sub.coil
flowing through the pre-charge contactor coil 60 that is greater
than pull-in current I.sub.pull_in may cause the contactor relay 72
to close, thus beginning a pre-charge of the main load 34. The
resistor 78 arranged with the contactor coil 74 and the contactor
relay 72 of the contactor 42c may reduce current through the
contactor coil 74 to be less than upper-bound current
I.sub.upper_bound and may further maintain current I.sub.coil
flowing through the contactor coil 74 being greater than pull-in
current I.sub.pull_in, where upper-bound current I.sub.upper_bound
is greater than pull-in current I.sub.pull_in.
Following closing of the contactor relay 72 that may initiate a
first stage of pre-charging the main load 34, the battery
controller 16 may be configured to at block 106 determine whether
the first stage of pre-charging the main load 34 has been
completed, such as based on voltage across the contactor 42d. In
one example, the battery controller 16 may measure voltage across
the contactor 42d for a predefined period of time and/or a
predefined number of times prior to determining whether a
pre-charge of the main load 34 has been completed. At block 108 the
battery controller 16 may issue a diagnostic message in response to
determining at block 106 that the first stage of pre-charging the
main load 34 has not been completed, e.g., voltage across the open
contactor 42d is greater than a voltage drop across the resistor 78
after a predefined period of time.
In response to determining at block 106 that the first stage of
pre-charging the main load 34 has been completed, e.g., voltage
across the open contactor 42d is equal to a voltage drop across the
resistor 78, the battery controller 16 may at block 110 issue a
command to open the switch 76 initiating a second stage of
pre-charging the main load 34. At block 112 the battery controller
16 may be configured to determine whether the second stage of
pre-charging the main load 34 has been completed, such as based on
voltage across the contactor 42d after a predefined period of time.
At block 108 the battery controller 16 may issue a diagnostic
message in response to determining at block 112 that the second
stage of pre-charging the main load 34 has not been completed,
e.g., voltage across the contactor 42d is greater than a predefined
threshold after a predefined period of time.
In response to determining at block 112 that the second stage of
pre-charging the main load 34 has been completed, e.g., voltage
across the contactor 42d is less than a predefined threshold, the
battery controller 16 may at block 114 issue one or more commands
to operate the switch 76 such that current flowing through the
contactor coil 74 is greater than hold current I.sub.hold. The
battery controller 16 may further issue a command to close the
contactor 42d. The process 100 may then end. In some instances, the
process 100 may be repeated in response to receiving a signal
indicative of a request to close the contactors 42c, 42d or in
response to another signal or request.
The processes, methods, or algorithms disclosed herein may be
deliverable to or implemented by a processing device, controller,
or computer, which may include any existing programmable electronic
control unit or dedicated electronic control unit. Similarly, the
processes, methods, or algorithms may be stored as data and
instructions executable by a controller or computer in many forms
including, but not limited to, information permanently stored on
non-writable storage media such as ROM devices and information
alterably stored on writeable storage media such as floppy disks,
magnetic tapes, CDs, RAM devices, and other magnetic and optical
media. The processes, methods, or algorithms may also be
implemented in a software executable object. Alternatively, the
processes, methods, or algorithms may be embodied in whole or in
part using suitable hardware components, such as Application
Specific Integrated Circuits (ASICs), Field-Programmable Gate
Arrays (FPGAs), state machines, controllers or other hardware
components or devices, or a combination of hardware, software and
firmware components.
The words used in the specification are words of description rather
than limitation, and it is understood that various changes may be
made without departing from the spirit and scope of the disclosure.
As previously described, the features of various embodiments may be
combined to form further embodiments of the invention that may not
be explicitly described or illustrated. While various embodiments
could have been described as providing advantages or being
preferred over other embodiments or prior art implementations with
respect to one or more desired characteristics, those of ordinary
skill in the art recognize that one or more features or
characteristics may be compromised to achieve desired overall
system attributes, which depend on the specific application and
implementation. These attributes may include, but are not limited
to cost, strength, durability, life cycle cost, marketability,
appearance, packaging, size, serviceability, weight,
manufacturability, ease of assembly, etc. As such, embodiments
described as less desirable than other embodiments or prior art
implementations with respect to one or more characteristics are not
outside the scope of the disclosure and may be desirable for
particular applications.
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